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Title:

Recent results of the sootless diesel fuel oxymethylene ether

Document type:
Konferenzbeitrag
Contribution type:
Textbeitrag / Aufsatz
Author(s):
Pélerin, D.; Gaukel, K.; Härtl, M.; Wachtmeister, G.
Pages contribution:
439-456
Abstract:
An important reason for the future use of liquid fuels in internal combustion engines lies in their high energy density. However, regarding the sustainability of internal combustion engines, the challenges fuel supply, CO2-emissions and pollutants have to be faced. Particularly the pollutants issue can be solved by the introduction of oxygenated synthetic fuels for reasons of their molecular structure. Especially oxymethylene ethers (OME) have shown a great potential in diesel engines, by avoiding the soot-NOx trade-off completely. In this work the latest experimental results of the Technical University Munich with different oxymethylene ethers are introduced. Besides OME1, the simplest oligomer with the constitutional formula CH3 O(-CH2 O)n CH3 and n=1, also a mixture of different OMEn with n=3-6 is investigated. A paraffinic diesel fuel (PDF) is used as a diesel reference fuel. The investigations are carried out on a heavy-duty single cylinder diesel research engine with a displacement of 1.75 l and a compression ratio of 17. No modifications are made to the hardware components of the engine, except of the replacement of elastomer sealings. The results show that both OME1 and the mixture of OME3 6 burn without soot emissions despite of high EGR rates and very low rail pressure levels in a medium load point. Thus, the NOx level can be reduced down to < 0.2 g/kWhi solely by engine internal measures. For OME1 two operating strategies with the aim to reduce NOx-emissions internally by high EGR levels (λ = 1.0 and λ =1.1) are investigated in a wide range of the engine map. From the point of indicated efficiency, a strategy with λ = 1.1 shows clearly advantages compared to stoichiometric engine operation. There is also a benefit in raw emissions like methane or formaldehyde while operating at λ = 1.1. This is important because the conversion ratio of the DOC for methane is very low at typical exhaust gas temperatures. Compared to PDF the combustion duration can be shortened with OME in low load points whereby efficiency advantages result. At higher load points the combustion is restrained by the fuel mass flow of the injector. As a consequence of the lower energy density of OME, its advantages in fast combustion are diminished by longer duration of injector energizing, which leads to the requirement of adapted injector nozzles for further investigations.
Keywords:
alternative diesel fuels, lowest emissions
Book / Congress title:
4. Internationaler Motorenkongress
Date of congress:
21.-22.02.2017
Date of publication:
22.02.2017
Year:
2017
Pages:
16
Reviewed:
nein
Language:
en
TUM Institution:
Lehrstuhl für Verbrennungskraftmaschinen
Format:
Text
 BibTeX